Production of cyanogen compounds.



PRODUCTION-OF CYANQG'EN GOMEOUNDS.

No Drawing.

-' Production of Cyanogen Compounds, of

which the following is a specification.

My invention relates to that class in which a cyanogen compound isproduced through the combination of an initially combined metal of thealkaline group, :With carbon and With nitrogen, which may be initiallyfree, or admixed with other gases and in which the solid materialsemployed are first finely comminuted and then mixed to gether With orWithout a catalytic material, suitable for lowering the temperature forthe combination of the active elements, and is directed among otherthings, toward pro- Xiding such an extended surface of the componentmaterials for instant contact with the nitrogen as to reduce the timerequired for the completion of the chemical reactions involved, to aninconsiderable period, and to the intermittent removal of the treatedmaterial from the reducing chamber while .in a plastic condition andwithout substantial interruption, of the continuity of the process.

An examination of the art shows that in the production of cyanogencompounds by combining free nitrogen with an initially combined alkalimetal and carbon, iron was used as a catalytic agent to reduce thetemperature at which the reaction occurred, as far back as in 1835),when a mixture of coke, cinder or coals potassium carbonate, (potash orpearl ash) and iron turnings ground to a coarse powder were employed byLewis Thompson for the production of potassium cyanid by heating themixture in the presence of atmospheric air, (English periodical, TheMechanics Magazine No. 822 p. Here by the powdering of the iron anextended catalytic surface was obtained.

The proportions in which the solid materials were used have since beenonly slightly varied.

This (Thompsons) process consists in igniting a mixture of two partspotash, two parts coke or bituminous coal (steinkohlen) and one partironturnings in an open vessel Specification of Letters Patent.

iatented ent. 31%, i ilfd.

Application filed June 30, 1917. Serial l lo. 171363.

permitting the access 013 air. Erdmann and Marchand in the JomnalPro/ttsobc @hcm-ic vol. 26, page 413.

This formula has since been varied only by increasing the proportion ofpowdered iron.

Where an iron tube is used as a catalyt c agent as in Siepermann s'process English Patents 13,697 of 1889, 935-0 and 9351 of 1906 themixture is in the )roportion of one part of sodium carbonate to twoparts of charcoal.

In the manufacture of cyanamids and also of cyanide Where the reactiontakes place with the alkali compound in a plastic condition, that isbelow the fusion point of the material, an absorption method is used forfixin the nitrogen in the mass of? material which is placed in a largeretort and the nitrogen is introduced therein under slight pressure. The methods are described as ioL lows:

in the manufacture of cyanamid: The calcium car-bid is reduced to theconsistency of flour and thereafter the process deriates into twodistinct lines of treatment. At Odda (Norway) the crushed carbid placedin cylimlricai vertical roorts holding 3()0500 kilos. The absorption ofnitrogen proceeds for thirty to forty hours, and is known to be completeby reading the controlling: meter. 7 i

"William Barbour, London {1M5} pp. (31%33.

At l esterreg'eln, Pians di'lrta and other Continental works the processof manufacture is quite i'liil'ercnt. Here the powdered carbid is placedin horizontal retorts similar to the retorts used in making coal gas:these are heated externally to 800-1000 C. by being placed in agrasiircd furnace while a stream of nitrogen forced i no the retorts forabsorption by the cal-bid" Idea/"2 p.

in Buchers process U. 5%. Patent 1,120.68? he uses the absorption metmademploying a briqueted material, the preparation oi which he describes atlength assigning the follow ing reasons for abandoning the use ofpowdered material: page 3, line 35 and follow ing Flt is hence moreadvantageous to use the charge in briqucted form to avoid thedisadvantages inherent in the use powders since wi h the latter there isa liability to the clogging of the small openings which admit thenitrogen, with the consequent disturbance of the process: while furthera sintered charge in the retort may be somewhat difficult to remove.

Upon trial of powdered charges of the' above description, incontinuously acting furnaces of the type hereinafter described, thedifficulties were found to be much greater than were subsequentlyencountered when briqueted charges were used: while further with thepowder, under mechanical force, including the action of gravity, theheated charge became compact or gradually briqueted so that aftercooling it was very diflicult to remove it with an iron chisel andhammer. The advantage of the use of powdered material over a briquetedmass or bulk such as he employs is stated by Bucher (p. 2 line 92) asfollows: In the first of my copending applications, it is shown that thecyanid formation takes place very rapidly when the charge used is inform of powder f thus showing that proximity of the particles of carbonto those of iron is not an essential to rapid or complete reactionbetween the active materials. a,

In all of these absorption methods for fixing the free nitrogen orammonia gas in combination, the capacity of the furnace is limited bythe time required for the nitrogen gas to permeate the mixture.

- At the Westerregeln and other Continental works above cited, theoverheating of the walls ensues, and the cyanamid, on cooling, sets to arocklike mass on the walls of the retorts and has to be forcibly knockedout. Hence the retorts are subjected to a severe wear and tear. Imlustrial Nitrogen Cora wands (owl ]L';c )l0sivcs, page (33.

From this review of the state of the art it is evident that the use ofpowdered materials in the proportions of tWo parts of carbon to one ofthe alkali compound and of iron in requisite quantity to exert acatalytic effect. in lowering tem 'ierature, is not novel; up to thepresent time however the absorption of nitrogen into a bulk of materialwith its attendant disadvantage of enormous consumption of time for thecompletion of the process has been and is necessary where the reactionis effected with the materials unfused.

And no practical way of removing the product from the retort when apowdered ,material is fed therein has been discovered.

I will now illustrate my process as applied to the production of sodiumcyanid. In this case the mixture will preferably comprise one part ofsoda ash or sodium carbonate (Na CO,,), three parts of powdered iron andthree parts of a carbonaceous substance, such as charcoal or coke, whichmaterialS are first reduced to a fine powder therewith, and I re ulatethe and then thoroughly mixed. The soda ash will be found to have coatedthe particles of iron and carbon, thus presenting an ex tended surfacefor contact with the nitrogen gas when they are raised to a suitabletemperature for con'ibination, while maintained in a diffused mass.

In order to secure contact of the nitrogen with the active materialsunder'these conditions I prefer to utilize an elongated section of ironpipe, or tube, which is p0si= tioncd vertically and preferably has aheight of 50 feet or thereabout and a di ameter or cross-section solimited that the heated material while descending by gravity from theupper part of the tube will substantially all of it engage with andadhere to the inner wall of the tube. When it is desired to increase thetonnage capacity of the tube the cross-section or diameter may beincreased and the tube mounted to be variably positioned at, a veryslight angle in any direction from the vertical center.

. I deliver a supply of the powdered mixture into such tube at or nearits upper end so that it will descend, by gravity, in a diffused massuntil it contacts with the inner wall of the tube and adheres thereto. Ialso deliver a supply of nitrogen, into the tube, at or near its lowerend: the nitrogen being preferably preheated to the temperature ofcombination for the carbon and the sodium content' of the sodiumcarbonate temperature of the nitrogen supply so that when tliehe'at ofcombination, generated by the chemical reactions occurring in the heatzone of the tube, is released, the temperature therein shall not besubstantially increased thereby. In practice I prefer to maintain atemperature of about 1000 to 1100 0., though the temperature may bevaried and yet produce the cyanid in commercial quantities, I alsosupply heat externally to the furnace as necessary to maintain therequired temperature.

As when heated, the sodium carbonate and cyanid product becomes plasticand viscid, I take advantage of their adhesive quality to cause theheated particles of the mixture to contact with the inner wall of thetube in the course of their descent and adhere thereto, as heretoforeexplained thus accumulating and forming an inner skin or coatingthereon. Owing to the enormously extended surface of the activematerials exposed for contact, with the nitrogen, when pulverulentmaterials are used, the reaction is effected as to substantially all ofthe material before the particles become fixed by adhesion to the walland is completed as to all thereof in an inconsiderable periodthereafter. \Vhen it is desired to remove treated material from the walland chamber I preferably assure the effective treatment of all of theadhering remove the heated material While in a plasticcondition througha suitable valve at the bottom of the tube thus rendering the commercialtreatment of powdered material effective andpractical by continuous proc055. which is not substantially interrupted by these steps -for thedetachment and re moval of material.

I am filin on the same date herewith an appli 'ation 101' U. LettersPatent for an apparatus for producing cyanogen com-- pounds wherein Ishow a practical. method for the removal. of the plastic material fromthe inner face of the chamber Wall and for its removal from the chamberWhile in a plastic condition, but do not confine myself to the methodthere shown any suitable structure may be used and any suitable mechanical device for handling the plastic material and for its removalfrom the chamber without substantial interruption of the continuity ofthe process. Upon removal from the retort the treated material is givensuch further treatment in any usual manner as required to separate thecyanid content from the other material.

In the practice of my process I retain the.

. of a cyanamid, the catalytic agent and car loon being omitted and afinely comminuted carbid of the alkali'metal being employed. In suchcase, necessary temperature conditions arc observech the reaction willsubstantially occur while the .rnaterial is dif fused in the body of thereducing chamber or adhering to the Wall thereof, and the time requiredfor completing: the operation will be reduced to an inconsiderahleperiod. The material is removed from the Wall and Vil7l1- drawn from thetube at appropriate inter- VttlSWVllilG in a plastic condition, asheretofore described.- {h'ude cyanamid of the same metal may be added asa catalyzing agent.

I do not confine myself to the use of iron as catalytic agent as it iswell known that several other elements and substances may he used in.the place'thereof but ll find iron is the most economical for use on acommer- C" 1 l 12m ween? k p l preterablytuse decarnurized iron, it isknown that the reaction involved in the producing of a cyanid of analkali metal in the presence of carhurized iron results indecarhurization and likewise that when clecarhurized iron is used theiron undergoes no perceptible change and may be usec. repetite-ally.

My process may be varied by the use of hriquets such as described in theBucher process heretofore referred to and, as thus applied, thepulverulent materials mixed in the desired proportions are firstbriqueted and then continuously delivered to heated zone and permittedto descend gravity therein, but before suea desceutis completed, theyare caused to adhere to the inner Wall of the reducing chamber, acontinuous supply of nitrogen is delivered into the chamber. a reducingtemperature maintained therein. As the time. element is extended ly thenecessity for the absorption of the nitrogen by the briquets. thecoating on the Wall of the chamber is removed from the Wall andthe'furnace, at more extended intervals but is so removed While in aplastic condition, thus obviating the difficulties encountered in thepractice of his process.

Having thus specified, shown and. described the same, I claim as noveland my invention v 1. A process for the production. of a cyanogencompound from an initially combined alkali metal, initially freenitrogen and carbon, or a carbonaceous material, in the preseuceof acatalytic agent. which in cludes the pulverizing and mixing of thesolidv materials in such pi-rportions as to supply suliicient carbon forcombination with the alkali metal present when brought into the presenceof free nitrogen and sufficient quantity of a suitable catalytic agentto effectively reduce the temperature for combination of. activeparticipants in the reaction to form a cyanogen compound and ineffecting such. reaction by bringing a continuous supply of the mixedmaterial While in a diiiuscd mass into the presence of free nitrogen ina zone heated to the tem perature of combination for the activeelen'ients and in causing such diffused mass during its descent in thereducing chamber limiting such zone and in toe presence of such nitrogensupply to adhere to the inner Wall of such chamber and in removing theadhesive mass from the wall and the chambox, at appropriate intervals,While yet in a plastic conditiom substantially as described.

2. A process for the production of a cyanogen compound from an initiallycombined alkali metal, nitrogen admixed. with.

other gases and carbon, or a carbonaceous material, in the presence of acatalytic agent, which includes the pulverizing and mixing of the solidmaterials in such proportions as to supply sufficient carbon forcombination with the alkali metal present when brought into the presenceof such nitrogen and sufiicient quantity of a suitable catalytic agentto effectively reduce the temperature for combination of the activeparticipants in the reaction to form a cyanogen compound and ineffecting such reaction by bringing a continuous supply of the mixedmaterial while in a diffused mass into the presence of such nitrogen ina zone heated to the temperature of combination for the active elementsand in causing such diffused mass during its descent in the reducingchamber limiting such zone and in the presence of such nitrogen supplyto adhere to the inner Wall of such chamber and in removing the adhesivemass from the wall and the chamber, at appropriate intervals, while yetin a plastic condition, after sealing such chamber and showering into areaction space an inii:

supplying nitrogen thereto under for a short time, substantially asdescri 3. The process of producing carbon-nine gen-metal compounds whichcomprises mixture comprising an alkali metal pound and carbonaceousmatter, main ing in said reaction space an atmosphere consisting largelyof nitrogen, heating said reaction space to a temperature sufficient topromote a nitrogen fixing reaction among the materials, causing theproduct of said reaction to adhere to the Walls bounding the reactionspace and removing 'tiie accumulations of reaction product from theWalls at intervals.

Signed at New York, in the county of New York and State of New York,this seventh day of December, A. D. 1916.

JOHN DIX MORGAN.

Witnesses:

E. ROBERTS LEWIS, LAURA E. SMITH.

